dallmeyer



{No Model.) 3 Sheets-Sheet 1.

T. R. DALLMEYBR 8v' P. BBAUCHAMP.

PHOTOGRAPHIG SHUTTER.

Ne. 436,404. l Patented Sept. 16,1890.

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3 Sheets-Sheet 9.

(No Model.)

T. R. DALLMBYER it F. BBAUGHAMP.

PHOTOGVRAPHIG SHUTTBR.

Patented Sept. 16, 1890.

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THOMAS R. DALLMEYER, OF LONDON, AND FRANCIS BEAUOHAMP, OF

TOTTENHAM, ENGLAND.

PHOTOGRAPHIO SHUTTER.

SPECIFICATION forming part of Letters Patent No, 436,404, datedSeptember 16, 1890.

Application filed June 26, 1888. Serial No. 278,210. (No model.)

T0 all 10.71.0771, t may concern.-

Be it known that we, THOMAS RUDOLPH DALLMEYER, optician, residing at 25Newman Street, London, in the county of Middlesex and Kingdom of GreatBritain, and FRANCIS BEAUCHAMP, engineer, residing at High Cross,Tottenham, in the county of Middlesex and Kingdom of Great Britain, bothsubjects of the Queen of Great Britain, have invented certain new anduseful Improvements in Photographic Lens Shutters, of which thefollowing is a specification.

Our invention relates to improvements in the shutters employed inconnection with photographic lens-mounts for the purpose ot admittinglight to the camera for a greater or less lengthy of time and forexcluding light therefrom altogether when required.

Our improvements relate more especially to arrangements andconstructions of shutters which open and close from and to the center insuch manner that the opening produced by such shutters is always centralor concentric with the center of the lens-mount and more or lessapproximating to a circular or regular polygonal form whether fully openor partially closed.

Our invention consists of certain improvements in the details of theshutter-operating devices, substantially as hereinafter set forth andclaimed.

In the drawings hereto annexed, Figure l is a side view of part of alens mount with the shutter thereinconstructed in accordance with ourinvention. Fig. 2 is a longitudinal ysection of same, taken on line l lof Fig. l.

Fig. 3 is an elevation of the circular box containing the shuttermechanism, with the disk J and tube AX (seen in Fig. 2) removed, theshutter being shown wide open. Fig. et is an elevation with the shutterpartially closed, and Fig. 5 is a similar view with the shuttercompletely closed.

A represents part of the tube ot the lensmount.

B is a circular box or chamber at the end of the tube A, containing theshutter. O is a cover to the said box B.

A is a tube formed with or secured in the center of the disk C andforming a prolongation of the tube A.

D, E, F, G, H, and I are metallic leaves or chopper-shaped pieces, whichtogether form the shutter. These leaves turn, respectively, onfulcrum-pins D', E', F', G', H', and I', which take into holes in thebottom of the box B. These leaves have respectively fixed to them on theside opposite to the fulcrumpins other pins D2, E2, F2, G2, H2, and I2.

J is a disk iitting easily into and turning to a limited extent in thebox B. It is provided with radial slots K, corresponding to andreceiving the pins D2, E2, F2, G2, H2, and I2.

L is a slotted arm projecting from the disk J through an opening in theside of the box B. The inner edges of the aforesaid leaves arepreferablyformed to the arc of a circle, so that when they are openedout to their widest extent, as shown in Fig. 3, their said inner edgesforni a complete circle, as shown. It will now be understood that byturning the disk J in the direction of the arrow in Fig. 3 by means ofthe arm L the slots K in the disk J press against the pins D2, E2, F2,G2, H2, and I2, causing the corresponding leaves to turn inward on theirfulcrum-pins D', E', F', G', H', and I', so that the inner segmentaledges of such leaves intersect each other, so as to form an openingwhich gradually decreases in size as the arm L is moved, but which isalways concentric to or symmetrical with regard to the center andapproximates more or less to the circular form..

In Fig. at theleaves are shown partly turned and intersecting eachother, so as to form a shutter about half-closed, and in Fig. 5 they areshown turned to such an extent as to inl tersect in such manner as toform an entirelyclosed shutter. When the arm L is moved in a directionopposite to the arrow in Fig. 3, the slots K act on the pins D2, E2, F2,G2, H2, and I2, so as to turn the leaves in the opposite direction andthereby to form a gradually-enlarging opening.

The opening and closing of these shutters, in order to give thenecessary exposure to the picture in the camera, may be effected bymoving the arm L by hand 5 vbut We prefer to move it by automatic means,and for that purpose we employ the mechanism shown at the IOO upper partof Figs. 1, 3, 4, and 5 and to a scale v the needful exposure.

twice as large in Figs. 6, 7, and 8. Fig. Gis a section of thisapparatus. Fig. 7 is an elevation of the same withthe cover'ot thecontainingcase removed, and Fig. 8 is a front view. M is a case securedby a iiange M to the back of the box B. Nis an ordinary clock-workspring, one end of which is connected to the arbor-NX and the other endto the case M. This arbor NX carries a spur-wheel N', gearing with apinion N2 on an arbor N5, having a milled handle N4 external to the caseM. The arbor N5 hassecured on it the ratchet-wheel N5, which isprevented from turning by the spring-pawl O. P is a crank-arm externalto the case M and fixed on the arbor NX. The crank-pin P of this cranktakes into'the slot L of the arm L. By turning the milled handle N4 thearbor NX may be turned partly round, winding up the spring N and turningthe crank P into a position diametrically opposite to that shown in Fig.5, the shutter being closed, as shown in that figure. The spring-pawlOwill hold the arbor NX and crank P in that position by means of theratchet-wheel N5 until it is required to open and close the shutter togive Then by pressing the pawl O out of gear with the ratchet-wheel N5the arbor NX is released to the action of its spring, which causes it tomake a partial revolution which brings the crank P back into theposition shown in Fig. 5. As the crank-pin causes the shutter to openand close.

P passes from its upper position into that shown in'Fig. 3, it causesthe arm L to move from the position shown in Fig. 5into the positionshown in Fig. S-that is, to open the shutter to its full extent. Thenthe further movement of the .crank-pin P into the position shown in Fig.5 causes the arm L to move back from the position ,shown in Fig. 3 tothat shown in Fig. -that is, to close the shutter again. Q is a stop toprevent the crank P from going beyond the position shown in Fig. 5. Thusthe half-revolution of the crank P The speed with which this opening andclosing action is effected may be regulated Within certain limits bymeans of a friction-brake arrangement (shown in Figs. 6' and 7) arrangedto act on the ratchet-wheel N5. R is a kind of pinchers, the closedendof which is secured by the pin R and the open end of which embracesbetween its branches the aforesaid ratchet-wheel N5, leather washers R2being preferably interposed between the branches of the pinchers and thesaid ratchet-wheel. R5 is a screw, the head of which extends to theoutside of the case M, and has on it an indexpointer R4, moving over agraduated scale, as shown in Fig. 8. By tightening up or slackening thisscrew R5 more or less by means of the index-pointer R4 frictionalresistance may be imparted to the ratchet-wheel N5, and the 'speed ofits revolution, and consequently that of the arbor NX and crank P,thereby regulated to a certain extent.

Although it is necessary always to close the shutter entirely, it issometimes desirable'to open it only partially, so as not to admit the 4the arm L is moved, and consequently the amount to which the shutter isopened, while the, complete closing is eected Whatever bc the positionof the crank-pin P on the crankarm P, as shown in Fig. 5.

Figs. 9, lO, and 11 show a modification of the above-describedarrangements. In this case the shutter is shown composed of four leavesD, E, F, and G, instead of six, and the tube A, instead of beingdivided, as inFigs. 1 to 5, is continuous, being merely slotted for thepassage of the leaves through it, as shown in Fig. 10, the continuity ofthe tube being preserved by the parts A A2 A5 A4. These leaves turn onpivots D', E', F, and G', and the disk J, instead of having radial slotsfor actuating the shutter-leaves, has L-shaped slots K, placed as shownin Figs. 9 and 10, the eect of which is that a movement of the arm L ineither direction both opens and closes the shutter-leaves.

To eiect the movement of the arm L automatically, the arm S is urged bya spring contained in the box S in the direction of the arrow. This armS is connected by the link S5 with the arm L by means of a stud S5, ad-

loo

justable in the slot L by means of the clampl ing-nut S4. T is a studfixed on the arm L and passing through the slot T in the box. U is alatch-lever pivoted at UX, pressed by a spring U toward the stud T. Whenthe arm L is in the position shown in Fig. 9 and the shutter is closed,the stud T is latched by the part U2 of the latch-lever U, so that thespring-urged arm S cannot draw the arm L.

to the right; but if the latch-lever U be pressed down the stud T isliberated and the spring-urged'arm S is then free to act and draws thearm L to the right, turning the disk J and causing the slots K thereinto turn the shutter-leaves first outward, so as to open the shutter, andhen inward, so as to close the same again. The time occupied in eectingthis opening and closing of the shutter can be regulated to a certainextent by moving the stud S5 up or down in the slot L. Raising itincreases the time occupied in opening and closing, and lowering itdecreases the time.

When it is required to obtain a comparatively long exposure-that is tosay, to hold the shutter open longer than the arrangelments abovedescribed will admit of-we applay a second latch V to the latch-lever U.

IIO

Such latch V turns on a fulcru'm-pin-V on the latch-lever U, and has atail-piece V5 and projecting part V5. It also carries a bridlepiece V4,by which it can be connected to or coupled with the latch-lever U, asshown in Fig. 9. When the two latches are so coupled together, the latchV is inoperative, and the releasing of the latch U from the stud Tallows the arm L to effect the opening and then theimmediate closing ofthe shutter, as above described; but when it is required to hold theshutter open for a certain length of time and then to close it thebridle-piece Vi is turned into the position shown in Fig. 10, and theouter end of the latch V is pressed down, elevating the projecting partV3 and bringing the tail-piece V2 against the stud T. A slight furtherpressure on the outer end of the latch V releases the part U2 of thelatch-lever U from the stud T, Fig. 9, and the arm L then moves into theposition shown in Fig. 10, with the shutter open. The stud T, comingagainst the part V3 of the latch V, holds the arm L in that positionuntil the outer end ot' the latch V is released, when the stud T pressesthe somewhat inclined surface of the projection V3 downward, and isthereby released, and the arm L completes its movement to the right,closing the shutter.

Figs. 12, 13, 1i, 15, 16, and 17 illustrate an arrangement whereby theshutter may be made to serve not only as a shutter, but also as adiaphragm or stop with variable size of aperture, and with arrangementswhereby the speed of opening and closing may be regulated within certainlimits, and whereby the shutter may be held open for any required lengthof time. Fig. 12 is an end view of a lens-mount, showing the shutterclosed. Fig. 13 is a partial plan of Fig. 12 g and Figs. 14, 15, 1G,and17 are detail views to a larger scale of the apparatus for regulatingthe time and for holding the shutter open.

The amount to which the shutter is opened is regulated in the followingway: M is a case containing clock-work arrangements which actuate acrank-pin Pin a manner somewhat similar to that already described inreference to Figs. 3, at, and 5. This crank-pin passes through thesemicircular slot PX in the side of the case M and takes into the slot Lin the arm L. The case M is adjustable circumferentially to a limitedextent on the box B by means of the tangent-screw WV gearing into teethon the edge of the flange M of the case M and turning in bearings W',fixed on the edge of the box B. The flange M is guided by screws M2 M3,passing through slots M4, and can be clamped in place by the milledscrew M3. In the position shown in Fig. 12 the crank-pin P is free tomake a complete half-revolution in the slot PX, and therefore to movethe arm L to the left in the figure sufficiently to open the shutter toits fullest extent; but if the case M be moved to the right in Fig. 12the crank-pin P is no longer able to traverse the entire length of theslot PX, because it brings the arm L against its stop in the positionshown in Fig. 12 before it can itself reach either the upper or lowerend of the slot PX-that is to say, the crankpin P can only describe asegment ot' the halfcircle, the versine of which varies according to theposition of the case M on the box B. Consequently the arm L is onlymoved to the left in the same proportion, and therefore the shutter isonly opened in like proportion. By these means the shutter may be usedin place of a stop or diaphragm, the size of the aperture being variedto correspond to that which would be used if the ordinary diaphragm wereemployed. The same effect can be produced as before explained inconnection with Figs. 3, 4c, and 5 by making the crank-pin adjustableinto various positions on the crank-arm.

The mechanism for operating' the crankpin P consists of a spring-barreland windinggear somewhat similar to that shown in Figs. 6 and 7, similarletters of reference relating to like parts in Figs. 6, 7, 8, 14, 15,16, and 17.

In the arrangements shown in Figs. 12 to 17 the brake mechanism forregulating the time occupied by the opening and closing of theshutter-that is, the length of exposure, when such is not required to beinstantaneous-consists of a brake-strap R, preferably lined withleather, iixed to a pin R at one end, passing half-round a brake-drum RXon the axis N3 of the ratchet-wheel N5, and connected at the other endto a screw R3, passing through the case M and having an indexpointer R"working as a nut thereon. This index moves over a graduated scale, asshown in Fig. 16, and by turning the said index the pressure of thebrake-strap R on the brakedrum R may be varied so as to increase ordecrease the time of exposure within certain limits.

In order to hold the shutter open during any required length of time,whether for the purpose of obtaining a long exposure or while focusing,we employ the trigger and retaining arrangements shown in Figs. 11i, 15,16, and 17. O is a pawl held in gear with the teeth of the ratchet-wheelN5 by the spring O. O2 is an arm extending from the Said pawl andterminating in a inger-piece just outside the case M. O3 is another armex* tending from the arm O2 and bent at right angles, as shown in Fig.14T. O'L is a stop on a disk O5, secured on the ratchet-wheel arbor N3.OG is a latch which prevents the arm O2 moving beyond a certain distancewhen necessary, as hereinafter described. 1t will now be understood thatif the latch O be moved aside and the arm O2 be pressed by itsprojecting fingenpiece, so as to draw the pawl O out of gear with theratchet-wheel N5, the bent part of the arm O3 will be brought into thepath of the stop O4 and the revolution of the arbor N3 will be arrestedwhen the said stop comes against the arm. The portion of a revolutionmade, however, by the arbor N before it is stopped by the arm O3 issufficient to allow the crank-pin P to revolve far enough to open theshutter to the extent defined by the adjustment of the case M on the boxB or of the crank-pin in the slot of its crank, as the case may be, andso long as the arm O3 IOC IIO

is held forward, so as to prevent the stop O4 from passing, so long willthe shutter be held open. If, however, the arm O3 be moved back farenough to release the stop O4, but not far enough to place the pawl O ingear with the ratchet-Wheel N 5, the arbor N3 will be free to continueits rotation and to allow the crank-pinP to complete its partialrotation and to close the shutter. The exact p0- sition of the arm 02 toenable this to be done is defined by the latch O6, as when the arm O2bears against this latch the arbor N3 is free to revolve. This latch O6therefore serves also as a means of defining the proper position of thearm O2, and 'consequently of the pawl O when itis required to allow thecrankpin P to eect the opening and'closing of the shutteruninterruptedly.

We claiml. In mechanism for operating camera-shutters, the device foreecting the movement of the shutteractuating disk J automatically,consisting of the spring-actuated crankpin P, held and released bymeans'of a ratchet-Wheel N5 and a spring-pawl O and acting on an arm Lof thesaid disk J, substantially as set forth.

2. The device for regulating within certain limits the time occupied inopening and closing the shutter, consisting of a friction-brake R,pressing against the side or periphery of a brake Wheel' or drum with apressure adv ferentially on the lens-mount, substantially as described.i

In testimony that we claim the foregoing as our invention We have signedour names in presence of two subscribing Witnesses.

THOS. R. DALLMEYER. F. BEAUCHAMP.

.Wtnessesz y G. F. WARREN, Ncciztary Public, 17 Gracechurch Street, Lon-W. A. SMITH, 117 Stoke N ewington Road, London.

